The invention relates to isolated nucleic acids and polypeptides derived from Streptococcus pneumoniae that are useful as molecular targets for diagnostics, prophylaxis and treatment of pathological conditions, as well as materials and methods for the diagnosis, prevention, and amelioration of pathological conditions resulting from bacterial infection.
Streptococcus pneumoniae (S. pneumoniae) is a common, spherical, gram-positive bacterium. Worldwide it is a leading cause of illness among children, the elderly, and individuals with debilitating medical conditions (Breiman, R. F. et al., 1994, JAMA 271: 1831). S. pneumoniae is estimated to be the causal agent in 3,000 cases of meningitis, 50,000 cases of bacteremia, 500,000 cases of pneumonia, and 7,000,000 cases of otitis media annnually in the United States alone (Reichler, M. R. et al., 1992, J. Infect. Dis. 166: 1346; Stool, S. E. and Field, M. J., 1989 Pediatr. Infect. Dis J. 8: S11). In the United States alone, 40,000 deaths result annually from S. pneumoniae infections (Williams, W. W. et al., 1988 Ann. Intern. Med. 108: 616) with a death rate approaching 30% from bacteremia (Butler, J. C. et al., 1993, JAMA 270: 1826). Pneumococcal pneumonia is a serious problem among the elderly of industrialized nations (Kxc3xa4yhty, H. and Eskola, J., 1996 Emerg. Infect. Dis. 2: 289) and is a leading cause of death among children in developing nations (Kxc3xa4yhty, H. and Eskola, J., 1996 Emerg. Infect. Dis. 2: 289; Stansfield, S. K., 1987 Pediatr. Infect. Dis. 6: 622).
Vaccines against S. pneumoniae have been available for a number of years. There are a large number of serotypes based on the polysaccharide capsule (van Dam, J. E., Fleer, A., and Snippe, H., 1990 Antonie van Leeuwenhoek 58: 1) although only a fraction of the serotypes seem to be associated with infections (Martin, D. R. and Brett, M. S., 1996 N. Z. Med. J. 109: 288). A multivalent vaccine against capsular polysaccharides of 23 serotypes (Smart, L. E., Dougall, A. J. and Gridwood, R. W., 1987 J. Infect. 14: 209) has provided protection for some groups but not for several groups at risk for pneumococcal infections, such as infants and the elderly (Makel, P. H. et al. 1980 Lancet 2: 547; Sankilampi, U., 1996 J. Infect. Dis. 173: 387). Conjugated pneumococcal capsular polysaccharide vaccines have somewhat improved efficacy, but are costly and, therefore, are not likely to be be in widespread use (Kxc3xa4yhty, H. and Eskola, J., 1996 Emerg. Infect. Dis. 2: 289).
At one time, S. pneumoniae strains were uniformly susceptible to penicillin. The report of a penicillin-resistant strain of (Hansman, D. and Bullen, M. M., 1967 Lancet 1: 264) was followed rapidly by many reports indicating the worldwide emergence of penicillin-resistant and penicillin non-susceptible strains (Klugman, K. P., 1990 Clin. Microbiol. Rev. 3: 171). S. pneumoniae strains which are resistant to multiple antibiotics (including penicillin) have also been observed recently within the United States (Welby, P. L., 1994 Pediatr. Infect. Dis. J. 13: 281; Ducin, J. S. et al., 1995 Pediatr. Infect. Dis. J. 14: 745; Butler, J. C., 1996 J. Infect. Dis. 174: 986) as well as internationally (Boswell, T. C. et al., 1996; J. Infect. 33: 17; Catchpole, C., Fraise, A., and Wise, R., 1996 Microb. Drug Resist. 2: 431; Tarasi, A. et al., 1997 Microb. Drug Resist. 3: 105).
A high incidence of morbidity is associated with invasive S. pneumoniae infections (Williams, W. W. et al., 1988 Ann. Intern. Med. 108: 616). Because of the incomplete effectiveness of currently available vaccines and antibiotics, the identification of new targets for antimicrobial therapies, including, but not limited to, the design of vaccines and antibiotics, which may help prevent infection or that may be useful in fighting existing infections, is highly desirable.
The present invention fulfills the need for diagnostic tools and threapeutics by providing bacterial-specific compositions and methods for detecting, treating, and preventing bacterial infection, in particular S. pneumoniae infection.
The present invention encompasses isolated polypeptides and nucleic acids derived from S. pneumoniae that are useful as reagents for diagnosis of bacterial infection, components of effective antibacterial vaccines, and/or as targets for antibacterial drugs, including anti-S. pneumoniae drugs. The nucleic acids and peptides of the present invention also have utility for diagnostics and therapeutics for S. pneumoniae and other Streptococcus species. They can also be used to detect the presence of S. pneumoniae and other Streptococcus species in a sample; and in screening compounds for the ability to interfere with the S. pneumoniae life cycle or to inhibit S. pneumoniae infection. More specifically, this invention features compositions of nucleic acids corresponding to entire coding sequences of S. pneumoniae proteins, including surface or secreted proteins or parts thereof, nucleic acids capable of binding mRNA from S. pneumoniae proteins to block protein translation, and methods for producing S. pneumoniae proteins or parts thereof using peptide synthesis and recombinant DNA techniques. This invention also features antibodies and nucleic acids useful as probes to detect S. pneumoniae infection. In addition, vaccine compositions and methods for the protection or treatment of infection by S. pneumoniae are within the scope of this invention.
The nucleotide sequences provided in SEQ ID NO: 1-SEQ ID NO: 2603, a fragment thereof, or a nucleotide sequence at least 99.5% identical to a sequence contained within SEQ ID NO: 1-SEQ ID NO: 2603 may be xe2x80x9cprovidedxe2x80x9d in a variety of medias to facilitate use thereof. As used herein, xe2x80x9cprovidedxe2x80x9d refers to a manufacture, other than an isolated nucleic acid molecule, which contains a nucleotide sequence of the present invention, i.e., the nucleotide sequence provided in SEQ ID NO: 1-SEQ ID NO: 2603, a fragment thereof, or a nucleotide sequence at least 99.5% identical to a sequence contained within SEQ ID NO: 1-SEQ ID NO: 2603. Uses for and methods for providing nucleotide sequences in a variety of media is well known in the art (see e.g., EPO Publication No. EP 0 756 006)
In one application of this embodiment, a nucleotide sequence of the present invention can be recorded on computer readable media. As used herein, xe2x80x9ccomputer readable mediaxe2x80x9d refers to any media which can be read and accessed directly by a computer. Such media include, but are not limited to: magnetic storage media, such as floppy discs, hard disc storage media, and magnetic tape; optical storage media such as CD-ROM; electrical storage media such as RAM and ROM; and hybrids of these categories such as magnetic/optical storage media. A person skilled in the art can readily appreciate how any of the presently known computer readable media can be used to create a manufacture comprising computer readable media having recorded thereon a nucleotide sequence of the present invention.
As used herein, xe2x80x9crecordedxe2x80x9d refers to a process for storing information on computer readable media. A person skilled in the art can readily adopt any of the presently known methods for recording information on computer readable media to generate manufactures comprising the nucleotide sequence information of the present invention.
A variety of data storage structures are available to a person skilled in the art for creating a computer readable media having recorded thereon a nucleotide sequence of the present invention. The choice of the data storage structure will generally be based on the means chosen to access the stored information. In addition, a variety of data processor programs and formats can be used to store the nucleotide sequence information of the present invention on computer readable media. The sequence information can be represented in a word processing text file, formatted in commercially-available software such as WordPerfect and Microsoft Word, or represented in the form of an ASCII file, stored in a database application, such as DB2, Sybase, Oracle, or the like. A person skilled in the art can readily adapt any number of data processor structuring formats (e.g. text file or database) in order to obtain computer readable media having recorded thereon the nucleotide sequence information of the present invention.
By providing the nucleotide sequence of SEQ ID NO: 1-SEQ ID NO: 2603, a fragment thereof, or a nucleotide sequence at least 99.5% identical to a sequence contained within SEQ ID NO: 1-SEQ ID NO: 2603 in computer readable form, a person skilled in the art can routinely access the sequence information for a variety of purposes. Computer software is publicly available which allows a person skilled in the art to access sequence information provided in a computer readable media. Examples of such computer software include programs of the xe2x80x9cStaden Packagexe2x80x9d, xe2x80x9cDNA Starxe2x80x9d, xe2x80x9cMacVectorxe2x80x9d, GCG xe2x80x9cWisconsin Packagexe2x80x9d (Genetics Computer Group, Madison, WI)and xe2x80x9cNCBI toolboxxe2x80x9d (National Center for Biotechnology Information).
Computer algorithms enable the identification of S. pneumoniae open reading frames (ORFs) within SEQ ID NO: 1-SEQ ID NO: 2603 which contain homology to ORFs or proteins from other organisms. Examples of such similarity-search algorithms include the BLAST [Altschul et al., J. Mol. Biol. 215:403-410 (1990)] and Smith-Waterman [Smith and Waterman (1981) Advances in Applied Mathematics, 2:482-489] search algorithms. These algorithms are utilized on computer systems as exemplified below. The ORFs so identified represent protein encoding fragments within the S. pneumoniae genome and are useful in producing commercially important proteins such as enzymes used in fermentation reactions and in the production of commercially useful metabolites.
The present invention further provides systems, particularly computer-based systems, which contain the sequence information described herein. Such systems are designed to identify commercially important fragments of the S. pneumoniae genome. As used herein, xe2x80x9ca computer-based systemxe2x80x9d refers to the hardware means, software means, and data storage means used to analyze the nucleotide sequence information of the present invention. The minimum hardware means of the computer-based systems of the present invention comprises a central processing unit (CPU), input means, output means, and data storage means. A person skilled in the art can readily appreciate that any one of the currently available computer-based systems is suitable for use in the present invention. The computer-based systems of the present invention comprise a data storage means having stored therein a nucleotide sequence of the present invention and the necessary hardware means and software means for supporting and implementing a search means. As used herein, xe2x80x9cdata storage meansxe2x80x9d refers to memory which can store nucleotide sequence information of the present invention, or a memory access means which can access manufactures having recorded thereon the nucleotide sequence information of the present invention.
As used herein, xe2x80x9csearch meansxe2x80x9d refers to one or more programs which are implemented on the computer-based system to compare a target sequence or target structural motif with the sequence information stored within the data storage means. Search means are used to identify fragments or regions of the S. pneumoniae genome which are similar to, or xe2x80x9cmatchxe2x80x9d, a particular target sequence or target motif. A variety of known algorithms are known in the art and have been disclosed publicly, and a variety of commercially available software for conducting homology-based similarity searches are available and can be used in the computer-based systems of the present invention. Examples of such software includes, but is not limited to, FASTA (GCG Wisconsin Package), Bic_SW (Compugen Bioccelerator, BLASTN2, BLASTP2 and BLASTX2 (NCBI) and Motifs (GCG). BLASTN2, A person skilled in the art can readily recognize that any one of the available algorithms or implementing software packages for conducting homology searches can be adapted for use in the present computer-based systems.
As used herein, a xe2x80x9ctarget sequencexe2x80x9d can be any DNA or amino acid sequence of six or more nucleotides or two or more amino acids. Aperson skilled in the art can readily recognize that the longer a target sequence is, the less likely a target sequence will be present as a random occurrence in the database. The most preferred sequence length of a target sequence is from about 10 to 100 amino acids or from about 30 to 300 nucleotide residues. However, it is well recognized that many genes are longer than 500 amino acids, or 1.5 kb in length, and that commercially important fragments of the S. pneumoniae genome, such as sequence fragments involved in gene expression and protein processing, will often be shorter than 30 nucleotides.
As used herein, xe2x80x9ca target structural motif,xe2x80x9d or xe2x80x9ctarget motif,xe2x80x9d refers to any rationally selected sequence or combination of sequences in which the sequence(s) are chosen based on a specific functional domain or three-dimensional configuration which is formed upon the folding of the target polypeptide. There are a variety of target motifs known in the art. Protein target motifs include, but are not limited to, enzymatic active sites, membrane spanning regions, and signal sequences. Nucleic acid target motifs include, but are not limited to, promoter sequences, hairpin structures and inducible expression elements (protein binding sequences).
A variety of structural formats for the input and output means can be used to input and output the information in the computer-based systems of the present invention. A preferred format for an output means ranks fragments of the S. pneumoniae genome possessing varying degrees of homology to the target sequence or target motif. Such presentation provides aperson skilled in the art with a ranking of sequences which contain various amounts of the target sequence or target motif and identifies the degree of homology contained in the identified fragment.
A variety of comparing means can be used to compare a target sequence or target motif with the data storage means to identify sequence fragments of the S. pneumoniae genome. In the present examples, implementing software which implement the BLASTP2 and bic_SW algorithms (Altschul et al., J. Mol. Biol. 215:403-410 (1990); Compugen Biocellerator) was used to identify open reading frames within the S. pneumoniae genome. A person skilled in the art can readily recognize that any one of the publicly available homology search programs can be used as the search means for the computer-based systems of the present invention.
The invention features S. pneumoniae polypeptides, preferably a substantially pure preparation of an S. pneumoniae polypeptide, or a recombinant S. pneumoniae polypeptide. In preferred embodiments: the polypeptide has biological activity; the polypeptide has an amino acid sequence at least 60%, 70%, 80%, 90%, 95%, 98%, or 99% identical to an amino acid sequence of the invention contained in the Sequence Listing, preferably it has about 65% sequence identity with an amino acid sequence of the invention contained in the Sequence Listing, and most preferably it has about 92% to about 99% sequence identity with an amino acid sequence of the invention contained in the Sequence Listing; the polypeptide has an amino acid sequence essentially the same as an amino acid sequence of the invention contained in the Sequence Listing; the polypeptide is at least 5, 10, 20, 50, 100, or 150 amino acid residues in length; the polypeptide includes at least 5, preferably at least 10, more preferably at least 20, more preferably at least 50, 100, or 150 contiguous amino acid residues of the invention contained in the Sequence Listing. In yet another preferred embodiment, the amino acid sequence which differs in sequence identity by about 7% to about 8% from the S. pneumoniae amino acid sequences of the invention contained in the Sequence Listing is also encompassed by the invention.
In preferred embodiments: the S. pneumoniae polypeptide is encoded by a nucleic acid of the invention contained in the Sequence Listing, or by a nucleic acid having at least 60%, 70%, 80%, 90%, 95%, 98%, or 99% homology with a nucleic acid of the invention contained in the Sequence Listing.
In a preferred embodiment, the subject S. pneumoniae polypeptide differs in amino acid sequence at 1, 2, 3, 5, 10 or more residues from a sequence of the invention contained in the Sequence Listing. The differences, however, are such that the S. pneumoniae polypeptide exhibits an S. pneumoniae biological activity, e.g., the S. pneumoniae polypeptide retains a biological activity of a naturally occurring S. pneumoniae enzyme.
In preferred embodiments, the polypeptide includes all or a fragment of an amino acid sequence of the invention contained in the Sequence Listing; fused, in reading frame, to additional amino acid residues, preferably to residues encoded by genomic DNA 5xe2x80x2 or 3xe2x80x2 to the genomic DNA which encodes a sequence of the invention contained in the Sequence Listing.
In yet other preferred embodiments, the S. pneumoniae polypeptide is a recombinant fusion protein having a first S. pneumoniae polypeptide portion and a second polypeptide portion, e.g., a second polypeptide portion having an amino acid sequence unrelated to S. pneumoniae. The second polypeptide portion can be, e.g., any of glutathione-S-transferase, a DNA binding domain, or a polymerase activating domain. In preferred embodiment the fusion protein can be used in a two-hybrid assay.
Polypeptides of the invention include those which arise as a result of alternative transcription events, alternative RNA splicing events, and alternative translational and postranslational events.
In a preferred embodiment, the encoded S. pneumoniae polypeptide differs (e.g., by amino acid substitution, addition or deletion of at least one amino acid residue) in amino acid sequence at 1, 2, 3, 5, 10 or more residues, from a sequence of the invention contained in the Sequence Listing. The differences, however, are such that: the S. pneumoniae encoded polypeptide exhibits a S. pneumoniae biological activity, e.g., the encoded S. pneumoniae enzyme retains a biological activity of a naturally occurring S. pneumoniae. 
In preferred embodiments, the encoded polypeptide includes all or a fragment of an amino acid sequence of the invention contained in the Sequence Listing; fused, in reading frame, to additional amino acid residues, preferably to residues encoded by genomic DNA 5xe2x80x2 or 3xe2x80x2 to the genomic DNA which encodes a sequence of the invention contained in the Sequence Listing.
The S. pneumoniae strain, 14453, from which genomic sequences have been sequenced, has been deposited on Jun. 26, 1997 in the American Type Culture Collection and assigned the ATCC designation #55987.
Included in the invention are: allelic variations; natural mutants; induced mutants; proteins encoded by DNA that hybridize under high or low stringency conditions to a nucleic acid which encodes a polypeptide of the invention contained in the Sequence Listing (for definitions of high and low stringency see Current Protocols in Molecular Biology, John Wiley and Sons, New York, 1989, 6.3.1-6.3.6, hereby incorporated by reference); and, polypeptides specifically bound by antisera to S. pneumoniae polypeptides, especially by antisera to an active site or binding domain of S. pneumoniae polypeptide. The invention also includes fragments, preferably biologically active fragments. These and other polypeptides are also referred to herein as S. pneumoniae polypeptide analogs or variants.
The invention further provides nucleic acids, e.g., RNA or DNA, encoding a polypeptide of the invention. This includes double stranded nucleic acids as well as coding and antisense single strands.
In preferred embodiments, the subject S. pneumoniae nucleic acid will include a transcriptional regulatory sequence, e.g. at least one of a transcriptional promoter or transcriptional enhancer sequence, operably linked to the S. pneumoniae gene sequence, e.g., to render the S. pneumoniae gene sequence suitable for expression in a recombinant host cell.
In yet a further preferred embodiment, the nucleic acid which encodes an S. pneumoniae polypeptide of the invention, hybridizes under stringent conditions to a nucleic acid probe corresponding to at least 8 consecutive nucleotides of the invention contained in the Sequence Listing; more preferably to at least 12 consecutive nucleotides of the invention contained in the Sequence Listing; more preferably to at least 20 consecutive nucleotides of the invention contained in the Sequence Listing; more preferably to at least 40 consecutive nucleotides of the invention contained in the SequenceListing.
In another aspect, the invention provides a substantially pure nucleic acid having a nucleotide sequence which encodes an S. pneumoniae polypeptide. In preferred embodiments: the encoded polypeptide has biological activity; the encoded polypeptide has an amino acid sequence at least 60%, 70%, 80%, 90%, 95%, 98%, or 99% homologous to an amino acid sequence of the invention contained in the Sequence Listing; the encoded polypeptide has an amino acid sequence essentially the same as an amino acid sequence of the invention contained in the Sequence Listing; the encoded polypeptide is at least 5, 10, 20, 50, 100, or 150 amino acids in length; the encoded polypeptide comprises at least 5, preferably at least 10, more preferably at least 20, more preferably at least 50, 100, or 150 contiguous amino acids of the invention contained in the Sequence Listing.
In another aspect, the invention encompasses: a vector including a nucleic acid which encodes an S. pneumoniae polypeptide or an S. pneumoniae polypeptide variant as described herein; a host cell transfected with the vector; and a method of producing a recombinant S. pneumoniae polypeptide or S. pneumoniae polypeptide variant; including culturing the cell, e.g., in a cell culture medium, and isolating an S. pneumoniae polypeptide or an S. pneumoniae polypeptide variant, e.g., from the cell or from the cell culture medium.
In another series of embodiments, the invention provides isolated nucleic acids comprising sequences at least about 8 nucleotides in length, more preferably at least about 12 nucleotides in length, and most preferably at least about 15-20 nucleotides in length, that correspond to a subsequence of any one of SEQ ID NO: 1-SEQ ID NO: 2603 or complements thereof. Alternatively, the nucleic acids comprise sequences contained within any ORF (open reading frame), including a complete protein-coding sequence, of which any of SEQ ID NO: 1-SEQ ID NO: 2603 forms a part. The invention encompasses sequence-conservative variants and function-conservative variants of these sequences. The nucleic acids may be DNA, RNA, DNA/RNA duplexes, protein-nucleic acid (PNA), or derivatives thereof.
In another aspect, the invention features, a purified recombinant nucleic acid having at least 50%, 60%, 70%, 80%, 90%, 95%, 98%, or 99% homology with a sequence of the invention contained in the Sequence Listing.
In another aspect, the invention features nucleic acids capable of binding mRNA of S. pneumoniae. Such nucleic acid is capable of acting as antisense nucleic acid to control the translation of mRNA of S. pneumoniae. A further aspect features a nucleic acid which is capable of binding specifically to an S. pneumoniae nucleic acid. These nucleic acids are also referred to herein as complements and have utility as probes and as capture reagents.
In another aspect, the invention features an expression system comprising an open reading frame corresponding to S. pneumoniae nucleic acid. The nucleic acid further comprises a control sequence compatible with an intended host. The expression system is useful for making polypeptides corresponding to S. pneumoniae nucleic acid.
In another aspect, the invention features a cell transformed with the expression system to produce S. pneumoniae polypeptides.
In yet another embodiment, the invention encompasses reagents for detecting bacterial infection, including S. pneumoniae infection, which comprise at least one S. pneumoniae-derived nucleic acid defined by any one of SEQ ID NO: 1-SEQ ID NO: 2603, or sequence-conservative or function-conservative variants thereof. Alternatively, the diagnostic reagents comprise polypeptide sequences that are contained within any open reading frames (ORFs), including complete protein-coding sequences, contained within any of SEQ ID NO: 1-SEQ ID NO: 2603, or polypeptide sequences contained within any of SEQ ID NO: 2604-SEQ ID NO: 5206, or polypeptides of which any of the above sequences forms a part, or antibodies directed against any of the above peptide sequences or function-conservative variants and/or fragments thereof.
The invention further provides antibodies, preferably monoclonal antibodies, which specifically bind to the polypeptides of the invention. Methods are also provided for producing antibodies in a host animal. The methods of the invention comprise immunizing an animal with at least one S. pneumoniae-derived immunogenic component, wherein the immunogenic component comprises one or more of the polypeptides encoded by any one of SEQ ID NO: 1-SEQ ID NO: 2603 or sequence-conservative or, function-conservative variants thereof; or polypeptides that are contained within any ORFs, including complete protein-coding sequences, of which any of SEQ ID NO: 1-SEQ ID NO: 2603 forms a part; or polypeptide sequen ID NO: 2604-SEQ ID NO: 5206; or polypeptides of which any of SEQ ID NO: 2604-SEQ ID NO: 5206 forms a part. Host animals include any warm blooded animal, including without limitation mammals and birds. Such antibodies have utility as reagents for immunoassays to evaluate the abundance and distribution of S. pneumoniae-specific antigens.
In yet another aspect, the invention provides a method for detecting bacterial antigenic components in a sample, which comprises the steps of: (i) contacting a sample suspected to contain a bacterial antigenic component with a bacterial-specific antibody, under conditions in which a stable antigen-antibody complex can form between the antibody and bacterial antigenic components in the sample; and (ii) detecting any antigen-antibody complex formed in step (i), wherein detection of an antigen-antibody complex indicates the presence of at least one bacterial antigenic component in the sample. In different embodiments of this method, the antibodies used are directed against a sequence encoded by any of SEQ ID NO: 1-SEQ ID NO: 2603 or sequence-conservative or function-conservative variants thereof, or against a polypeptide sequence contained in any of SEQ ID NO: 2604-SEQ ID NO: 5206 or function-conservative variants thereof.
In yet another aspect, the invention provides a method for detecting antibacterial-specific antibodies in a sample, which comprises: (i) contacting a sample suspected to contain antibacterial-specific antibodies with a S. pneumoniae antigenic component, under conditions in which a stable antigen-antibody complex can form between the S. pneumoniae antigenic component and antibacterial antibodies in the sample; and (ii) detecting any antigen-antibody complex formed in step (i), wherein detection of an antigen-antibody complex indicates the presence of antibacterial antibodies in the sample. In different embodiments of this method, the antigenic component is encoded by a sequence contained in any of SEQ ID NO: 1-SEQ ID NO: 2603 or sequence-conservative and function-conservative variants thereof, or is a polypeptide sequence contained in any of SEQ ID NO: 2604-SEQ ID NO: 5206 or function-conservative variants thereof.
In another aspect, the invention features a method of generating vaccines for immunizing an individual against S. pneumoniae. The method includes: immunizing a subject with an S. pneumoniae polypeptide, e.g., a surface or secreted polypeptide, or active portion thereof, and a pharmaceutically acceptable carrier. Such vaccines have therapeutic and prophylactic utilities.
In another aspect, the invention features a method of evaluating a compound, e.g. a polypeptide, e.g., a fragment of a host cell polypeptide, for the ability to bind an S. pneumoniae polypeptide. The method includes: contacting the candidate compound with an S. pneumoniae polypeptide and determining if the compound binds or otherwise interacts with an S. pneumoniae polypeptide. Compounds which bind S. pneumoniae are candidates as activators or inhibitors of the bacterial life cycle. These assays can be performed in vitro or in vivo.
In another aspect, the invention features a method of evaluating a compound, e.g. a polypeptide, e.g., a fragment of a host cell polypeptide, for the ability to bind an S. pneumoniae nucleic acid, e.g., DNA or RNA. The method includes: contacting the candidate compound with an S. pneumoniae nucleic acid and determining if the compound binds or otherwise interacts with an S. pneumoniae polypeptide. Compounds which bind S. pneumoniae are candidates as activators or inhibitors of the bacterial life cycle. These assays can be performed in vitro or in vivo.